Solid fuel unit

ABSTRACT

A process for improving the initial igniting properties of a charcoal unit by first impregnating the unit with an inflammable liquid after the temperature of the liquid and charcoal has first been established at a predetermined value and thereafter sealing the liquid within the unit by dipping the latter within a molten solution of high-melting point paraffin wax, then cooling the paraffin coating in such a manner as not to detrimentally affect its appearance or vapor sealing characteristics.

United States Patent Davis, Jr. 51 Mar. 7, 1972 54] SOLID FUEL UNIT 3,356,469 12/1967 Stephenson et al ..44/6 [72] Inventor: George B. Davis, Jr. 7512 Mammy Road, 3,374,070 3/1968 Davis ..44/6

Bethesda 20014 FOREIGN PATENTS 0R APPLICATIONS [221 Filed 1970 477,770 10/1951 Canada ..44/6 [21] Appl. No.: 63,899

1 Primary Examiner-C. F. Dees Related US. Application Data [63] Continuation-impart of Ser. NO. 803,484, Feb. 28, [571 ABSTRACT 1969, abandoned. v A process for improving the initial igniting properties of a charcoal unit by first impregnating the unit with an inflamma- [52] US. Cl. ..44/6, 44/41 ble liquid after the temperature of the liquid and charcoal has 2; d h "C10! 9/ 15 2 2 first been established at a predetermined value and thereafter 1 le 0 Sea!!! l the the unit the latter a molten solution of high-melting point paraffin wax, then cool- [56] References Cited ing the paraffin coating in such a manner as not to detrimen- UNlTED STATES PATENTS tally affect its appearance or vapor sealing characteristics.

3,338,690 8/1967 Calhoun ..44/6 4 Claims, 2 Drawing Figures PATENTEUMAR 7 I972 I 3, 547, 40 3 IN VENT )R ar A w SOLID FUEL UNIT This application is a continuation-in-part of Ser. No. 803,484 filed Feb. 28, l969 and now abandoned. v

This invention relates generally to fire starters and, more particularly, to a fire starter of the charcoal briquette type. Such briquettes are used extensively for outdoor cooking wherewith the food is cooked directly over the burning coals. It is generally accepted that charcoal briquettes, of the type described, are extremely difficult to ignite. Normally, a fire of burning wood chips, paper, liquid fuel or the like is required to bring such briquettes to a kindling temperature. Even under ideal conditions uniform ignition of such charcoal units is difficult and frequently requires a considerable waiting period after ignition before the charcoal is ready for use.

Various methods have been tried heretofore in an attempt to facilitate this charcoal igniting procedure. One such method which is disclosed in US. Pat. No. 2.933378, provides for encapsulating the carbonous material of the briquette within a closely fitting fibrous pulplike envelope which, on burning, provides the igniting agent. Other such methods include coating the outer surface of the briquette with various forms of combustible materials which, on burning, is supposed to raise the temperature of the charcoal to kindling temperature. It has been found, however, when testing the effectiveness of these various briquette treating methods, that the heat generated thereby rarely, if ever, sufficiently heats the underlying charcoal sufficiently to affect uniform ignition. Generally, the flame resulting from the burning-off of these coatings, dies away long before all of the coating material has been completely consumed. This is particularly the case of the coated portion lying beneath and between the touching briquettes. As the flame dies, there exists a smoking and smoldering condition caused by the gassing-off of these coatings that produce a long lasting odious condition that persists well into the burning time of the briquette.

The present invention provides for a new and improved method for producing a charcoal unit for outdoor cooking wherein is sealed in a particular manner an inflammable liquid, one form thereof being a liquid hydrocarbon such as odorless mineral spirits that has been absorbed within the pores of the charcoal unit prior to the sealing operating. This charcoal unit, when ignited by the mere use of a match, burns rapidly with a hot, intense and continuous flame until all residue of the outer coating has been completely consumed. The flame will persist as long as there remains any portion of the hydrocarbon within the charcoal. This charcoal igniting operation produces little, if any, odor for the reason that all gasses from the starting agents have been burned by a persisting flame. The materials used in constructing the device of the present invention have been carefully chosen for their odorless characteristics, both before and during their burning. The result is an easily ignited charcoal unit that is shortly ready for the cooking operation.

It is an object of the present invention to provide a new and improved charcoal unit for outdoor cooking that is easily ignited, clean to handle, resistant to breakage, and waterproof in nature and the method of producing such a unit.

It is another object to provide an improved charcoal unit that may be ignited by the mere use of a match.

A still further object is to provide a charcoal unit for outdoor cooking that, during the igniting process, burns with a substantially odorless flame.

Another object is to provide a new and improved charcoal unit relatively cheap to manufacture thus bringing it competively within the price range of conventional charcoal briquettes, yet possessing all of the advantages herein set forth.

A still further object is to provide a new and improved method for manufacture of a solid fuel unit having all of the aforementioned desireable characteristics.

Other objects and advantages of the present invention will become more apparent upon reading the following description while referring to the accompanying drawings wherein:

FIG. 1 is a cross-sectional view of the fuel unit as shown in FIG. 2.

FIG. 2 is a plan view of the fuel unit of the invention.

Referring now to the drawings wherein FIG. I shows in cross section, the fuel unit of the invention as set forth in plan in FIG. 2 and which will hereafter be referred to generally by the numeral 5. This fuel unit iscomprised of a charcoal core 6 formed preferably from charred hardwood that has been compressed into the configuration shown. Pure uncompressed charcoal may be used if so desired. This charcoal core, though compressed as required to maintain the form illustrated, remains sufficiently porous as to readily absorb a low viscosity hydrocarbon that, during the processing of the unit, is applied to the outer surface thereof as by spraying or dipping. The shaded area 7 shows the penetration of such a liquid into the pores of the unit. Any hydrocarbonous material suitable for the purpose intended, must be relatively odorless as applied and when burning. One such hydrocarbon is known in the trade as odorless solvent or as odorless mineral spirits.

Such hydrocarbons, however, are highly volatile and would normally soon evaporate from the surface of the charcoal unit. To prevent this from occurring, the invention provides for sealing the outer surface of the unit with an inflammable vapor proof coating whereby evaporation of the hydrocarbon from the unit is reduced to a negligible degree. One outer coating that has been found particularly satisfactory for the purpose is a high melting point paraffin that liquefies at a temperature in excess of F. Such a paraffin, by reason of its compatibility with the hydrocarbon within the charcoal unit, if applied in the manner hereafter described, will bond readily to the latter to add greatly to its strength making it considerably more resistant to breakage and chipping. Further, this coating makes the unit clean to handle and relatively waterproof in character.

The hard wax coating 8 will, if penetrating well into the outer interstices of the unit, remain intact and perform its sealing function under high temperature storage conditions whereas other forms of inflammable coatings tried have cracked and separated from the charcoal unit. Such hard paraffin waxes, when exposed to a flame, will burn clean and relatively odorless.

With any sealant used, it is imperative that during the igniting operation, a flame is continually maintained until all vestage of this coating has burned completely from the char coal unit. Paraffins, as with the various other coatings tried, will burn odorless as long as a flame is present, but when gassing, as from a smoldering condition of the charcoal, a very odious condition results that persists long after the charcoal has reached a cooking temperature.

In operation, as a lighted match is applied to a charcoal unit processed as described herein, the paraffin coating rapidly melts away from the surface allowing escape of the gassing inflammable liquid within the charcoal unit. These gases burn with a hot and continuous flame until all of the paraffin coating has burned away. The flame will continue as long as there is any residue of the inflammable liquid within the charcoal unit. Long before this occurs, the charcoal unit has reached kindling temperature and will shortly, thereafter, be ready for the cooking operation.

The process necessary for producing the item described herein has been established by first fixing the temperature of the charcoal unit at some value preferably around F. This is substantially the temperature ofthe charcoal as it leaves the drying ovens during manufacture. While at this temperature, the charcoal is immersed in a chilled hydrocarbon solvent preferably having a boiling point of 350 F. or less. The temperature of the solvent being continuously maintained at a temperature below the temperature of the charcoal. A 50 F. to 100 F. temperature differential has been found satisfactory. As the heated charcoal unit is immersed in the chilled solvent, the air within the pores of the charcoal cools and upon contracting, draws into the charcoal unit a relatively large quantity of the solvent in a comparatively short period of time with very few bubbles emanating from the surface of the charcoal. This immersion operation should be conducted as rapidly as possible to prevent unnecessary cooling of the unit and may vary from 3 seconds to 25 seconds, depending upon the initial temperature differential between the solvent and charcoal and the size and density of the charcoal unit being treated. The greater the temperature differential, the shorter the immersion time in the solvent and desirably the less cooling effect upon the charcoal unit.

After removal of the charcoal from the solvent, the initial temperature of the unit continues to drop and by so cooling causes the solvent remaining upon and within the outer interstices of the unit to be rapidly drawn deep into the unit to leave the surface appearing dry and free of liquid solvent. To accelerate this surface drying effect, cool air may be directed over the hot charcoal unit as it is lifted from the solvent. After solvent treating and drying, the hot charcoal unit is immediately immersed in molten paraffin wax maintained at a temperature sufficiently hot, preferably between 200 F. and 350 F., as to rapidly volatize any solvent remaining upon or within the outer interstices of the unit thereby allowing the wax to enter and fill these outer interstices. The solvent used shall be sufficiently volatile at the temperature of the molten wax as to readily evaporate completely from the hot wax leaving it continually clean and uniform in composition. As the unit is removed from the wax, chilled air is directed over the surface of the unit to rapidly solidify the wax coating. The cold air serves not only to chill the wax coating, but by further cooling the charcoal unit before the wax hardens, causes the molten wax to be drawn deeper and more uniformly into the outer interstices of the unit. During the entire processing of the unit, the charcoal should be continually cooling from its initial hot state. The process should be completed long before the charcoal unit reaches ambient temperature. The final dipping of the charcoal within the hot paraffin, should be conducted as rapidly as possible to suitably coat and bond the paraffin to the unit without so greatly raising the internal temperature of the unit as to cause expansion within the unit and movement of the liquid solvent within the unit towards the outer surface.

One method found particularly satisfactory for chilling the paraffin coating after dipping without marring the surface thereof is to tumble the unit from the paraffin bath onto a moving pin studdied belt, the vertical pins upon the belt serving to support the charcoal unit in such an elevated manner that chilled air can readily circulate about the unit to rapidly solidify the paraffin upon the unit before it is tumbled from the belt onto a conveyor moving the unit to packaging.

The product and process for producing the same has proven far advantageous over others tried and found less satisfactory.

What I therefore claim:

1. A process for improving the initial ignition properties of a porous charcoal unit comprising the steps of immersing a substantially hot charcoal unit within an inflammable liquid hydrocarbon solvent having a boiling point preferably of 350 F. or less, the temperature of the solvent being previously established and continuously maintained at a value less than the temperature of the charcoal unit, maintaining the charcoal unit immersed within said solvent until the air within the pores of said hot charcoal has sufficiently cooled and contracted so as to draw within said unit a predetermined quantity of said solvent, removing said unit from said solvent and cooling until the surface of said unit appears substantially free of liquid solvent, immersing said unit in a molten paraffin wax, maintaining said unit immersed until sufficient vaporization of solvent from said unit which allows penetration of said wax into the outer interstices of said unit.

2. The process of claim 1 wherein the temperature of the paraffin wax at the time of immersion of the charcoal unit is preferably between the range of 200 F. to about 350 F.

3. The process of claim 1 wherein the temperature differential between the charcoal unit and the liquid hydrocarbon solvent at the beginning of the processing procedure is established at 50 F. or greater.

4. The charcoal unit made by the process of claim 1. 

2. The process of claim 1 wherein the temperature of the paraffin wax at the time of immersion of the charcoal unit is preferably between the range of 200* F. to about 350* F.
 3. The process of claim 1 wherein the temperature differential between the charcoal unit and the liquid hydrocarbon solvent at the beginning of the processing procedure is established at 50* F. or greater.
 4. The charcoal unit made by the process of claim
 1. 